Conversion of Chlorofluororopanes and Chlorofluropropenes to More Desirable Fluoropropanes and Fluororopenes

ABSTRACT

A process is provided comprising contacting and reacting the compound CF 3 CF 2 CHXCl, wherein X is H or Cl, or the compound CF 3 CF═CXCl, wherein X is H or Cl, with hydrogen in the presence of a catalyst consisting essentially of Cu, Ru, Cu—Pd, Ni—Cu, and Ni—Pd, to obtain as a result thereof reaction product comprising hydrofluoropropenes or intermediates convertible to said hydrofluoropropenes, notably CF 3 CF═CH 2  and CF 3 CH═CHF.

FIELD OF THE INVENTION

The present invention relates to chemical processes for convertingchlorofluoropropanes (HCFC) and chlorofluoropropenes (CFO) to moredesirable fluoropropanes and fluoropropenes, especially propenes thatare hydrofluoroolefins (HFO), i.e. free of Cl, and to intermediates fromwhich these HFOs can be obtained.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 8,399,722 discloses the hydrogenation of at least one of1,1-dichloro-2,3,3,3-tetrafluoropropene (CF₃CF═Cl₂, 1214ya) and1-chloro-2,3,3,3-tetrafluoropropene (CF₃CF═CHCl, 1224yd) in the presenceof catalyst composed of Pd supported on a carbon carrier to obtain2,3,3,3,-tetrafluoropropene (CF₃CF═CH₂, 1234yf), which is free ofchlorine and which has promise at least as a refrigerant exhibiting bothlow ozone depletion potential and low global warming potential. Example2 discloses the conversion rate 1214ya to 1234yf to be 75%, which canalso be considered the selectivity of the process. In Example 3 theselectivity dropped to 69%.

Processes are desired to obtain better results in the production ofHFO-1234yf, and/or to obtain HFO-1234ze (CF3CH═CHF),1,3,3,3-tetrafluoropropene), which is also free of chlorine and hasrefrigerant application, and/or which opens up new routes for obtainingdesirable HFOs such as HFO-1234yf or HFO-1234ze.

SUMMARY OF THE INVENTION

The present invention provides the process comprising contacting andreacting the compound CF₃CF₂CHXCl, wherein X is H or Cl, or the compoundCF₃CF═CXCl, wherein X is H or Cl, with hydrogen in the presence of acatalyst consisting essentially Cu, Ru, Cu—Pd, Ni—Cu, and Ni—Pd, toobtain as a result thereof reaction product comprisinghydrofluoropropenes or intermediates convertible to saidhydrofluoropropenes. When in the compound CF₃CF₂CHXCl, X is H, then thecompound is HCFC-235cb, and when Cl, the compound is HCFC-225ca. When inthe compound CF₃CF═CXCl, X is H, the compound is HCFO-1224yd, and when Xis Cl, the compound is CFO-1214ya. These are the reactant compounds inthis Hydrogenation Process.

Another embodiment of the present invention is the IntermediatesProcess, i.e. the process for converting the intermediates obtained inthe Hydrogenation Process to the desired hydrofluoropropenes. TheIntermediates Process comprises such reactions as hydrogenation,dehydrochlorination, and dehydrofluorination. The catalysts used in theHydrogenation Process are preferably those used in the hydrogenationreactions in the Intermediates Process.

The desired hydrofluoropropenes include HFO-1234yf (CF₃CF═CH₂),HFO-1234ze (CF₃CH═CHF), and HFO-1225zc (CF₃CH═CF₂).

Reaction pathways (reactant/reaction product) included in theHydrogenation Process and Intermediates Process are as follows:

When the reactant compound is HCFC-225ca, the reaction product comprisesHFO-1234yf (CF₂CF═CH₂). The reaction product may also comprise at leastone of HCFO-1224yd, and HCFC-235cb (CF₃CF₂CH₂Cl) which are intermediatesthrough which HFO-1234yf can be obtained. HCFO-1224yd can be converteddirectly to HFO-1234yf. HCFC-235cb can be converted indirectly toHFO-1234yf by first being converted to HCFO-1224yd, which is thenconverted to HFO-1234yf. The HCFC-235cb can also be converted directlyto HFO-1234yf, i.e. the reaction product of hydrogenating HCFC-235cbcomprises HFO-1234yf. This direct conversion can result when theHCFC-235cb is the reactant compound CF₃CF₂CHXCl, wherein X is H.

Typically, the reactant compound HCFC-225ca will be mixed withHCFC-225aa (CF₃CCl₂CHF₂), whereby the HCFC-225aa will accompany theHCFC-225ca in the contacting and reacting step. The resultanthydrogenation of the HCFC-225aa forms the reaction product comprising atleast one of HCFO-1224xe (CF₃CCl═CHF), HCFC-235da (CF₃CHClCHF₂), andHCFC-245fa (CF₃CH₂CF₂H), which are intermediates in the formation ofHFO-1234ze (CF₃CH═CHF). The hydrogenation of HCFC-225aa can also formHFO-1234ze directly.

When the intermediate is HCFO-1234xe, the reaction pathway to HFO-1234zeis to first form HCFC-23db (CF₃CHClHCH₂F), which can be converted toHFO-1234ze or 1234ze can be formed directly from 1234xe. When theintermediate is HCFC-235da, this can be converted to HFO-1234ze. Whenthe intermediate is HCFC-245fa , it can be converted to HFO-1234zedirectly.

When the reactant compound is either CFO-1214ya or 1224yd or a mixturethereof, the reaction product comprises HFO-1234yf.

DETAILED DESCRIPTION OF THE INVENTION

The hydrogenation reactions of the present invention (HydrogenationProcess and Intermediates Process) are preferably carried out in the gasphase in a corrosion-resistance reactor packed with a catalyticallyeffective amount of the catalyst at temperatures and pressures andcontact times effective to produce the reaction result desired for theparticular reaction. The hydrogenation reactions are preferably carriedout at atmospheric pressure or at higher or lower pressures.

The hydrogenation catalyst in each hydrogenation reaction in theHydrogenation Process consists essentially or Cu, Ru, Cu—Pd, Ni—Cu, orNi—Pd, with or without a support (carrier). These same catalysts arepreferably used in the hydrogenation reactions in the IntermediatesProcess, although the catalyst used in a particular hydrogenationreaction in the Intermediates Process can be different from the catalystused in a hydrogenation reaction in the Hydrogenation Process. Thecatalyst can include a support in each of the hydrogenation reactions.When a support is used as part of the catalyst, the Cu, Ru, Cu—Pd,Ni—Cu, or Ni—Pd can be loaded onto the support in a conventional mannerused for loading metals onto supports, including combinations of metals.For example, the catalysts can be prepared by either precipitation orimpregnation methods of the Cu, Ru, Cu—Pd, Ni—Cu, or Ni—Pd on a supportas generally described in Satterfield on pp. 87-112 in HeterogeneousCatalysts in Industrial Practice, 2^(nd) ed. (McGraw-Hill, New York,1991).The support is preferably inert, if not positively participativein the obtaining the desired result of the reaction, under theconditions of the reaction. The preferred support is carbon, which maybe treated to enhance its support function for the catalyst loaded ontothe carbon. One example of treatment is acid washing of the carbon.

When the catalyst is Cu—Pd or Ni—Pd, the Pd is preferably present in aminor amount as compared to the weight of the Cu or Ni. For, example,when the catalyst is Cu—Pd, the loading on the support in one embodimentis 0.1 to 20 wt % Cu and 0.1-1.0 wt % Pd. These same proportions canapply to the Ni-Pd catalyst. When the catalyst if Ni—Cu, the mole ratioof these metals can range from 1:99 to 99:1. In one embodiment, themolar ratio of these metals is about 1:1.

The foregoing description of catalysts applies to each of thehydrogenation reactions encompassed by the Hydrogenation Process andeach of the hydrogenation reactions of the Intermediates Process, whenthese catalysts are used in the Intermediate Process.

Each of the reactant compounds HCFC-235cb, HCFC-225ca, HCFO-1224yd, andCFO-1214ya are commercially available or can be prepared by knownprocesses in varying degrees of purity. Some impurities may participatein the hydrogenation reaction to form intermediates that can beconverted directly or indirectly to the desired HFP propene. Otherimpurities may be unaffected by the reaction

When the compound is CF₃CF₂CHXCl, wherein X is Cl, i.e. HCFC-225ca, thereaction product of the hydrogenation reaction in the presence ofcatalyst described above comprises the compound CF₃CF═CH₂ (HFO-1234yf).

This reaction product may also comprise at least one of the compoundsCF₃CF═CHCl (HCFO-1224yd) and CF₃CF₂CH2Cl (HCFC-235cb).

When the compound CF₃CF═CHCl is in the reaction product, this compoundcan be converted to the compound CF₃CF═CH2 by hydrogenation in thepresence of a catalyst such as described above. The catalyst can be thesame or different from the catalyst used to form the reaction product.The hydrogenation of the compound CF₃CF═CHCl to a reaction productcomprising CF₃CF═CH₂ is in effect practice of the present invention whenthe reactant compound is CF₃CF═CXCl, wherein X is H.

When the compound CF₃CF₂CH₂Cl is in the reaction product, this compoundcan be converted to the compound CF₃CF═CH_(2,) first bydehydrofluorination of said compound CF₃CF₂CH₂Cl to form the compoundCF₃CF═CHCl and then hydrogenation of said compound CF₃CF═CHCl in thepresence of catalyst as described above. Alternatively, the compoundCF₃CF₂CH₂Cl can be converted to CF₃CF═CH₂ by hydrogenation in thepresence of catalyst as described above.

When the reactant compound comprises HCFC-225ca, this compound willtypically be accompanied by the compound CF₃CCl2CHF₂ (HCFC-225aa) insaid contacting and reacting in the presence of the catalyst, wherebythe reaction product will also comprise at least one of the compoundsCF₃CCl═CHF (HCFO-1224xe), CF₃CHClCHF₂ (HCFC-235da), CF₃CH₂CF₂H(HCFC-245fa), and CF₃CH═CHF (HFO-1234ze) as reaction products of thehydrogenation of the HCFC-225aa during the hydrogenation of theHCFC-225ca. The HCFO-1234xe and HFC-245fa are both intermediates for theformation of CF₃CH═CHF (HFO-1234ze). The presence of HFO-1234ze in thereaction product means this compound is formed directly from thehydrogenation of HCFC-225aa.

When the reaction product compound is CF₃CCl═CHF (HCFO-1234xe), thiscompound is hydrogenated in the presence of catalyst as described aboveto form a reaction product comprising at least one of the compoundsCF₃CH═CHF (HFO-1234ze) and CF₃CHClCH₂F (HCFC-234db).

When the reaction product comprises the compound CF₃CHClCH₂F(HCFC-234db), this compound is converted to the reaction productcomprising the compound CF₃CH═CHF by dehydrochlorination of the compoundCF₃CHClCH₂F.

When the reaction product comprises the compound CF₃CHClCHF₂(HCFC-235da) this compound is converted to reaction product comprisingthe compounds CF₃CH═CF₂ or CF₃CH═CHF. In one embodiment, the HCFC-235dacan be dehydrochlorinated to form reaction product comprising HFO-1225zc(CF₃CH═CF₂). In another embodiment, the HCFC-235da is reacted with H₂ toremove both Cl and F (hydrodehalogenated) to form reaction productcomprising HFO-1234ze.

When the reaction product comprises the compound CF₃CH₂CF₂H (HCFC-245a),this compound can be dehydrofluorinated to form the reaction productcomprising CF₃CH═CHF (HFO-1234ze).

When the reactant compound is CF₃CF₂CHXCl, wherein X is H, i.e.(HCFC-235cb), the reaction product with H2 comprises the compoundCF₃CF═CH₂ (HFO-1234yf).

When the reactant compound is CF₃CF═CXCl, wherein X is Cl or CF₃CF═CXCl,wherein X is H, or a mixture of these reactant compounds, the reactionproduct of the hydrogenation reaction in the presence of catalyst asdescribed above comprises the compound CF₃CF═CH₂. Thus, CFO-1214ya orHCFO 1224yd can be the reactant compounds, one without the other, orthese compounds can be present as a mixture of reactant compounds.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a composition,process, method, article, or apparatus that comprises a list of elementsis not necessarily limited to only those elements but may include otherelements not expressly listed or inherent to such composition, process,method, article, or apparatus. Further, unless expressly stated to thecontrary, “or” refers to an inclusive or and not to an exclusive or. Forexample, a condition A or B is satisfied by any one of the following: Ais true (or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

The transitional phrase “consisting of” excludes any element, step, oringredient not specified. If in the claim such would close the claim tothe inclusion of materials other than those recited except forimpurities ordinarily associated therewith. When the phrase “consistsof” appears in a clause of the body of a claim, rather than immediatelyfollowing the preamble, it limits only the element set forth in thatclause; other elements are not excluded from the claim as a whole.

The transitional phrase “consisting essentially of” is used to define acomposition, method that includes materials, steps, features,components, or elements, in addition to those literally disclosedprovided that these additional included materials, steps, features,components, or elements do materially affect the basic and novelcharacteristic(s) of the claimed invention, especially the mode ofaction to achieve the desired result of any of the processes of thepresent invention. The term ‘consisting essentially of’ occupies amiddle ground between “comprising” and ‘consisting of’.

Where applicants have defined an invention or a portion thereof with anopen-ended term such as “comprising,” it should be readily understoodthat (unless otherwise stated) the description should be interpreted toalso include such an invention using the terms “consisting essentiallyof” or “consisting of.”

Also, use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

EXAMPLES

The concepts described herein will be further described in the followingExamples, which do not limit the scope of the invention as described inthe claims.

Example 1 Hydrogenation of 225ca to 1234y, 1224yd, and 235cb

10 cc 10% Cu/C is loaded into a 1/2 inch (1.3 cm) Hastelloy® C 227reactor. The catalyst is reduced at 250° C. with H₂ for 4 hours. ThenHCFC-225ca (GC analysis of HCFC-225ca reactant mixture in Table 1), isfed at 3.11 sccm with H₂ (10.5 sccm) at 325° C. and 350° C. atatmosphere pressure. The reaction product stream from the reactor isanalyzed by GC and GC-MS. The result of the hydrogenation reaction isshown in Table 2. HFO-1234yf, HCFO-1224yd and HCFC-235cb are reactionproducts made in this reaction.

TABLE 1 GC analysis of starting material 225ca mixture Compound 235cb225ca 225aa 225cb Others Mol % 1.44 83.25 4.14 11.14 0.03

TABLE 2 GC analysis of reaction product Temp Organic H₂ mol % of product° C. sccm sccm 1234yf 1224yd 1224xe 235cb 225ca 225aa 225cb 325 3.1110.5 1.51 1.82 2.07 3.58 73.87 1.35 11.52 350 3.11 10.5 4.71 6.77 2.4810.66 49.0. ND 12.66

Example 2 Hydrogenation of HCFC-225ca, Cu—Pd Catalyst

10 cc 0.5% Pd-8.5% Cu/C is loaded into a 1/2 inch (1.3 cm) Hastelloy® C227 reactor. The catalyst is reduced at 400° C. with H₂ for 4 hours.Then a 225ca/cb mixture (GC analysis of HCFC-225ca reactant mixture inTable 1), is fed at 3.11 sccm with H₂ (10.5sccm) at 125, 140 and 160° C.at atmosphere pressure. The stream from the reactor is analyzed by GCand GC-MS. The result of the test is shown in Table 3. HFO-1234yf,CFO-1224yd and HCFC-235cb are made in this reaction.

TABLE 3 GC analysis of reaction product Temp mol % of product ° C.1234yf 1224yd 1224xe 235cb 225ca 225aa 225cb 125 0.19 14.49 3.30 16.0351.03 0.95 12.80 140 0.38 29.17 3.44 34.29 17.39 0.82 12.56 160 0.7336.64 3.44 41.11 1.41 ND 12.5

This Example shows the conversion of 225ca and 1224yd to 1234yf in thatthe 1224yd is an intermediate to the formation of 1234yf.

Example 3 Hydrogenation of HCFC-235cb to HFO-1234yf

10 cc 10% Cu/C is loaded into a 1/2 inch (1.3 cm) Hastelloy® C 227reactor. The catalyst is reduced at 250° C. with H2 for 4 hours. Thenthe 235cb was fed at 3.5 sccm with H₂ (6 sccm) at 325 C and 350 C atatmosphere pressure. The stream from the reactor is analyzed by GC andGC-MS. The result of the test is shown in Table 4. The 235cb isconverted to 1234yf at a selectivity of 88 to 90%.

TABLE 4 GC analysis of reaction product Temp mol % of product ° C.1234yf 245cb 235cb 325 14.85 1.89 82.98 350 26.69 2.71 69.11

Example 4 Hydrogenation of 225ca to 1234y, 1224yd and 235cb, Ni—CuCatalyst

10 cc Johnson Matthey CP447 Ni—Cu/C is loaded into a 1/2 inch (1.3 cm)Hastelloy® C 227 reactor. The catalyst is reduced at 400° C. with H₂ for4 hours. Then 225ca (GC analysis of mixture in Table 5), is fed at 3.11sccm with H2 (11 sccm) at 225, 250, 275 and 300 C at atmospherepressure. The stream from the reactor is analyzed by GC and GC-MS. Theresult of the test is shown in Table 6. The 1234yf, 1224yd and 235cb aremade in this reaction.

TABLE 5 GC analysis starting 225ca mixture Mole Percent 225ca 225aa225cb Others 47.43% 3.09% 48.53% 0.95%

TABLE 6 GC analysis of reaction product (F22E is CF₃CF₂CH═CHCF₂CF₃) MolePercent Temp 1224 1224 ° C. 1234yf 1234ze F22E 1224yd-E isomer 1 235cbisomer 2 225ca 225aa 225cb Others 225 2.81% 0.00% 0.00% 0.85% 0.36%0.35% 0.11% 40.53% 2.90% 50.94% 1.16% 250 4.92% 0.00% 0.08% 1.72% 0.60%0.74% 0.23% 35.32% 2.53% 50.92% 2.94% 275 8.56% 0.00% 0.38% 3.44% 1.12%1.77% 0.44% 25.42% 1.87% 52.53% 4.46% 300 11.66% 0.16% 1.40% 5.82% 1.53%3.39% 0.70% 13.63% 1.13% 54.30% 6.27%

Example 5 Hydrogenation of 1214ya to 1234y and 1224yd, Ni—Cu Catalyst

10 cc Johnson Matthey CP447 Ni—Cu/C is loaded into a 1/2 inch (1.3 cm)Hastelloy® C 227 reactor. The catalyst is reduced at 400° C. with H₂ for4 hours. Then 1214ya is fed at 3.11 sccm with H₂ (11 sccm) at 225, 250,275 and 300° C. at atmosphere pressure. The stream from the reactor isanalyzed by GC and GC-MS. 1234yf and 1224yd are made in this reaction asshown in Table 7.

TABLE 7 GC analysis of reaction product Temp Mole Percent ° C. 1234yf1224yd 1214ya Others 225  2%  1% 95% 2% 250 18%  6% 70% 6% 275 23% 18%50% 9% 300 45% 23% 25% 7%

Example 6 Hydrogenation of 1214ya to 1234yf and 1224yd, Pd—Cu Catalyst

10 cc 0.5% Pd-8.5% Cu/C is loaded into a 1/2 inch (1.3 cm) Hastelloy® C227 reactor. The catalyst is reduced at 400° C. with H₂ for 4 hours.Then 1214ya is fed at 3.11sccm with H₂ (10.5sccm) at 125, 140 and 160°C. at atmosphere pressure. The stream from the reactor is analyzed by GCand GC-MS. The 1234yf and 1224yd are made as shown in Table 8.

TABLE 8 GC analysis of reaction product Temp mol % of product ° C.1234yf 1224yd 1214ya Others 125 0.6% 20% 69.4% 10% 140 1.2% 40% 38.8%20% 160  3% 60%  12% 25%

What is claimed is:
 1. Process comprising contacting and reacting thecompound CF₃CF₂CHXCl, wherein X is H or Cl, or the compound CF₃CF═CXCl,wherein X is H or Cl, with hydrogen in the presence of a catalystconsisting essentially of Cu, Ru, Cu—Pd, Ni—Cu, and Ni—Pd, to obtain asa result thereof reaction product comprising hydrofluoropropenes orintermediates convertible to said hydrofluoropropenes.
 2. Process ofclaim 1 wherein in said compound CF₃CF₂CHXCl, X is Cl, and said reactionproduct comprises the compound CF₃CF═CH_(2.)
 3. Process of claim 2wherein said reaction product also comprises at least one of thecompounds CF₃CF═CHCl and CF₃CF₂CH₂Cl.
 4. Process of claim 3 wherein saidcompound CF₃CF═CHCl is converted to the reaction product comprising thecompound CF₃CF═CH₂ by hydrogenation in the presence of a catalyst. 5.Process of claim 3 wherein said compound CF₃CF₂CH₂Cl is converted toreaction product comprising the compound CF₃CF═CH₂, first bydehydrofluorination of said compound CF₃CF₂CH₂Cl to form the compoundCF₃CF═CHCl and then hydrogenation of said compound CF₃CF═CHCl in thepresence of catalyst.
 6. Process of claim 3 wherein said compoundCF₃CF₂CH₂Cl is converted to reaction product comprising CF₃CF═CH₂ byhydrogenation in the presence of catalyst.
 7. Process of claim 2 whereinsaid compound CF₃CF₂CHXCl, wherein X is Cl, is accompanied by thecompound CF₃CCl₂CHF₂ in said contacting and reacting with hydrogen inthe presence of said catalyst, whereby said reaction product comprise atleast one of the compounds CF₃CCl═CHF, CF₃CHClCHF₂, CF₃CH₂CF₂H, andCF₃CH═CHF
 8. Process of claim 7 wherein said compound CF₃CCl═CHF ishydrogenated to form a reaction product comprising at least one of thecompounds CF₃CH═CHF and CF₃CHClCH₂F.
 9. Process of claim 8 whereincompound CF₃CHClCH₂F is converted to the reaction product comprising thecompound CF₃CH═CHF by dehydrochlorination.
 10. Process of claim 7wherein said compound CF₃CHClCHF₂ is converted to reaction productcomprising the compounds CF₃CH═CF₂ or CF₃CH═CHF.
 11. Process of claim 7wherein said compound CF₃CH₂CF₂H is dehydrofluorinated to form thereaction product comprising CF₃CH═CHF.
 12. Process of claim 1 wherein insaid compound CF₃CF₂CHXCl, X is H, and said reaction product comprisesthe compound CF₃CF═CH_(2.)
 13. Process of claim 1 wherein said compoundis CF₃CF═CXCl, wherein X is Cl or CF3CF═CXCl, wherein X is H or amixture thereof, and said reaction product comprises the compoundCF₃CF₂═CH₂.
 14. Process of claim 1 wherein said catalyst includes asupport.